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Rectifier Transformers
Rectifier transformers are different from normal power and distribution transformers because they are special transformers made for industrial application. A Rectifier transformer is a special application transformer which includes diodes and thyristors in the same tank.
Power electronic circuits that convert alternating current (ac) to direct current (dc) is called rectifier circuits. Similarly, the circuits which can convert direct current to alternating current are called inverter circuits. Both of these circuits are considered to be converters.
A transformer that has one of its windings connected to one of these converter circuits, as a dedicated transformer, is a rectifier transformer or converter transformer.
Rectifier transformers are used for industrial processes which require a significant direct current (dc) supply. Rectifier circuits are used to provide high-current dc for electrochemical processes like chlorine production as well as copper and aluminum production.
The classic example is provided by those industries that use electrolysis processes for the production of aluminum, and the high secondary currents, together with the harmonic currents generated by the rectification systems, must be taken into account fully when designing transformers to power such loads.
Two types of rectifiers are available: thyristor rectifiers and diode rectifiers.
In both cases, the transformers that power them must supply a gradually adjustable secondary voltage, which is normally produced via on-load tap changers (OLTC).
In cases in which the range of secondary voltages is high, the variation is produced through a regulation transformer, which can be located in a separate tank or in the same tank as the main transformer.
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